"Perceiving-the-present" refers to the idea that the visual system attempts to correct for the retina-to-percept delay. Changizi has shown that the classical geometrical illusions are consequences of this strategy of vision, and argues in this proposal that the same idea extends to more than two dozen other classes of illusion, such as (a) size contrast, (b) objects appear to move faster in parts of the visual field with high spatial frequency, (c) greater spatial frequency objects appear lower in luminance contrast, (d) motion contrast, (e) objects with greater luminance contrast appear both larger and faster, (f) targets in high luminance contrast surrounds appear lower in luminance contrast, (g) depth contrast, and (h) objects viewed more foveally appear both larger and faster. The proposed research would use two-alternative forced choice and nulling designs to test the more than two dozen predictions made by this hypothesis, with the hope of confirming what appears to be a central principle governing visual perception. Such elucidation of the function computed by the visual system is of great use, for without understanding function, one cannot make sense of the mechanisms implementing those functions in the brain.